- /*
- * Trim off a colon suffix if it's there.
- */
- host[strcspn(host, ":")] = '\0';
+ /*
+ * Trim a colon suffix off the hostname if it's there. In
+ * order to protect unbracketed IPv6 address literals
+ * against this treatment, we do not do this if there's
+ * _more_ than one colon.
+ */
+ {
+ char *c = host_strchr(host, ':');
+
+ if (c) {
+ char *d = host_strchr(c+1, ':');
+ if (!d)
+ *c = '\0';
+ }
+ }